Stay on target

Ever wonder what life could look like if we lived in a radically different universe? And no, I don’t mean “imagine alien life,” I mean, “try to think of a life-form that would exist if atoms couldn’t hold themselves together.” It’s a bizarre question and one that warps the very notion of what we even call life, but that’s exactly what a team of scientists at the University of Michigan did.

In a thought experiment, they tried to work out just what the universe would look like if you removed a fundamental force — in this case the weak force — to see if life would still be possible. Turns out, at least according to their math, that something resembling life could still survive in those conditions. And that’s admittedly pretty weird to think about.

If you’re unfamiliar, there are four fundamental forces in the universe. These are the underpinnings of almost everything that you an I interact with and include gravity, electromagnetism, and then the strong and weak nuclear forces. Gravity, in short, holds big things together, electromagnetism holds small ones together, the strong force holds the smallest ones together, and the weak force kinda rips some things apart from time to time.

If you combine these ideas with how the universe generally works — like how matter and anti-matter interact, or the mass of specific particles — you can start forming models about other possible universes. These rules, the universal constants, the particles that guide everything, and the ways in which all of these facets of reality interact are like the foundational rules of existence. And, you’d think, fiddling with one of them would break everything. But it doesn’t. At least not all the time.

“Although somewhat different from our own, such universes remain potentially habitable,” the paper’s abstract concludes. “Stellar evolution proceeds primarily through strong interactions, with deuterium first burning into helium, and then helium fusing into carbon. Low-mass deuterium-burning stars can be long-lived, and higher mass stars can synthesize the heavier elements necessary for life.”

It’s bizarre to wrap one’s head around how the universe would function if just one pillar was kicked out. You couldn’t, for instance, do this with the other three forces. At least, not that we know of. Electromagnetism keeps human-sized objects together, gravity would be needed to make stars, and the strong force holds the very protons and neutrons themselves in place. So what is it about the weak force that makes it replaceable, in a sense? And why does any of this matter?

“Looking at these questions can tell us something about our own universe,” study author Alex Howe told Gizmodo. The fact that stars would still be stable and would likely form, indicates something potentially more fundamental about them. Plus, it’s worth knowing just how essential the basic rules governing our reality really are.

Still, there’s no indication that a universe like this does actually exist. No one has uncovered any substantive evidence of a multiverse that we could perceive or study, so for the time being it’s outside the realm of classical science. It does make for a useful thought experiment though, and it’s great to see computer models backing this up at least a little bit.

I suppose I’m still stuck on the idea that it’d be bizarre if other universes had anything like our physics. Maybe it’s just me, or my relative lack of knowledge of advanced physics, but it’s hard to conceive of a separate universe that operates even a little like ours. The idea that light or anything at all would exist in a form that we could recognize it is strange to me.